1. Technical Field
The present invention relates to a liquid crystal device and a manufacturing method therefor, and an electronic apparatus.
2. Related Art
As an apparatus for displaying an image on a large screen using a liquid crystal device, there is a liquid crystal projector.
High luminance and high contrast are required for a projector. In this respect, a liquid crystal device of a vertical alignment mode can provide displays with high contrast.
Recently, this mode have been increasingly employed as the liquid crystal alignment mode of a liquid crystal device for a projector.
However, in the vertical alignment mode, liquid crystals align themselves perpendicularly to the surface of a substrate, and the interaction in the azimuth along which the liquid crystals fall when voltage is applied is weak.
If a pixel potential is applied to a pixel electrode and a counter electrode, an electric field generated from an end of the pixel electrode is inclined in a lateral direction in the vicinity of the pixel electrode.
Due to the electric filed in a lateral direction, liquid crystal molecules sometimes fall to cause a disclination by conflicts of liquid crystal molecules.
If a disclination occurs, display defects such as irregularity in brightness, decrease in contrast, and image sticking become visible.
To overcome such defects, in a normal vertical alignment mode, a method of tilting liquid crystal molecules a few degrees relative to a substrate surface is employed.
In this method, however, when the liquid crystal molecules are tilted by a few degrees, birefringence of liquid crystal molecules occurs.
The birefringence causes light leakage.
The light leakage decreases contrast.
To solve this problem, it is considered that liquid crystals are vertically aligned in pixel regions to ensure good contrast characteristics whereas liquid crystals are horizontally aligned mainly in non-display regions around the pixel regions to control the orientation of liquid crystal, thereby preventing a disclination.
For example, JP-A-2005-107373 and JP-A-2001-343651, which are first and second examples of related art, respectively, disclose liquid crystal devices having such a configuration.
In the first example, an inorganic alignment film is formed by an oblique deposition method, and the orientation angle of the inorganic alignment film is controlled by varying the thickness of the inorganic alignment film so that the azimuth of liquid crystals on the alignment film is controlled.
In a liquid crystal device in the second example, a vertical alignment regulating region is provided in a pixel region, and another alignment regulating region is provided in a region except the pixel region.
By this means, liquid crystal molecules in a pixel are oriented in one direction when voltage is applied.
However, the first example describes, “The pretilt angles in the display region and non-display region are 40 to 60 degrees with respect to the substrate normal direction. The pretilt angle in the non-display region is set larger than that in the display region.”
Therefore, a high-contrast display caused by vertical alignment at 90 degrees with respect to the substrate surface is not achieved.
The second example describes, “The pretilt angle in the display region with respect to the surface of an alignment film is 88 to 90 degrees, and the pretilt angle in the alignment regulating region is 0 to 87 degrees”.
The range of the pretilt angle is very large.
Actually, the orientation of liquid crystals often cannot be controlled according to the conditions, and therefore the liquid crystal device in this example cannot be used, i.e., a disclination occurs in some cases.